Cummins/Onan B43 / B48 — Out-of-Service Protection (over 30 days)

Maintenance · Engine

For the Cummins/Onan B43 / B48, from the Cummins/Onan owner's manual.

Applies to: Cummins/Onan B48, Cummins/Onan B43M engine, Cummins/Onan B48M engine

Procedure

1. Run the engine until it reaches normal operating temperature.
2. Turn off the fuel supply and run the engine until it stops.
3. Drain oil from the oil base while the engine is still warm; refill with fresh crankcase oil and attach a tag stating viscosity used.
4. Remove spark plugs; pour 1 ounce (2 tablespoons or 28 grams) of rust inhibitor or SAE #50 oil into the cylinders, crank over a few times, and reinstall spark plugs.
5. Service the air cleaner as outlined in MAINTENANCE.
6. Clean the governor linkage and protect by wrapping with a clean cloth.
7. Plug the exhaust outlet to prevent entrance of moisture, dirt and bugs.
8. Wipe the entire unit and coat rustable parts with a light film of grease or oil.
9. Provide a suitable cover for the entire unit.
10. If battery equipped, disconnect and follow standard battery storage procedure.

Full service-parts list: Cummins/Onan B48 →

Source: Cummins/Onan owner's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.

More Cummins/Onan repair guides →